Mechanochemical and Size Reduction Machines for Biorefining

In recent years, we have witnessed an increasing interest in the application of mechanochemical methods for processing materials in biomass refining techniques. Grinding and mechanical pretreatment are very popular methods utilized to enhance the reactivity of polymers and plant raw materials; however, the choice of devices and their modes of action is often performed through trial and error. An inadequate choice of equipment often results in inefficient grinding, low reactivity of the product, excess energy expenditure, and significant wear of the equipment. In the present review, modern equipment employing various types of mechanical impacts, which show the highest promise for mechanochemical pretreatment of plant raw materials, is examined and compared—disc mills, attritors and bead mills, ball mills, planetary mills, vibration and vibrocentrifugal mills, roller and centrifugal roller mills, extruders, hammer mills, knife mills, pin mills, disintegrators, and jet mills. The properly chosen type of mechanochemical activation (and equipment) allows an energetically and economically sound enhancement of the reactivity of solid-phase polymers by increasing the effective surface area accessible to reagents, reducing the amount of crystalline regions and the diffusion coefficient, disordering the supramolecular structure of the material, and mechanochemically reacting with the target substances.

TECHNOLOGY DEVELOPMENT FOR STRONG REDUCTION OF ENERGY CONSUMPTION AND CO2 EMISSION IN LIME AND CEMENT MANUFACTURE

The cement and lime industries are responsible for 8% of global CO2 emissions [1]. 35% of this CO2 share comes from fuel combustion to heat and decompose limestone to produce lime or “clinker” in an open atmosphere while the remaining 65% comes from limestone rock itself. Due to the new technology, high grades of both lime and CO2 were obtained faster and at much lower than conventional temperatures and CO2 was fully captured and utilized when using an HEVA reactor for limestone calcination. Clinker, a precursor of cement, was partly obtained at lower temperature when starting from HEVA lime and fine quartz after mechanochemical pretreatment.